class_docstr: Specification for user provided input data.
code: def _get(self, data, name):
      if self.internal:
          value = self.default
      elif self.required:
          try:
              value = data[name]
          except KeyError:
              # TODO: Add error message
              raise
      else:
          value = data.get(name, self.default)
  
      if self.preprocess is not None:
          value = self.preprocess(value)
  
      return value
  
imports: from typing import Any, Callable, Optional, Union, Type, Dict
  import numpy
  from gluonts.itertools import partition
  from gluonts.pydantic import parse_obj_as, BaseModel
  from ._freq import Freq
  from ._period import Period
  from ._time_frame import time_frame, TimeFrame
  from ._split_frame import split_frame, SplitFrame
label_desc: Use image node_id 2 for calling the Field obj's underlying member method code with example usage: obj._get(data, name) and returns: value